| 1 | /* |
| 2 | * Virtual Machine Generation ID Device |
| 3 | * |
| 4 | * Copyright (C) 2017 Skyport Systems. |
| 5 | * |
| 6 | * Author: Ben Warren <ben@skyportsystems.com> |
| 7 | * |
| 8 | * This work is licensed under the terms of the GNU GPL, version 2 or later. |
| 9 | * See the COPYING file in the top-level directory. |
| 10 | * |
| 11 | */ |
| 12 | |
| 13 | #include "qemu/osdep.h" |
| 14 | #include "qapi/error.h" |
| 15 | #include "qemu/module.h" |
| 16 | #include "hw/acpi/acpi.h" |
| 17 | #include "hw/acpi/aml-build.h" |
| 18 | #include "hw/acpi/vmgenid.h" |
| 19 | #include "hw/nvram/fw_cfg.h" |
| 20 | #include "hw/core/qdev-properties.h" |
| 21 | #include "hw/core/qdev-properties-system.h" |
| 22 | #include "migration/vmstate.h" |
| 23 | #include "system/physmem.h" |
| 24 | #include "system/reset.h" |
| 25 | #include "exec/cpu-common.h" |
| 26 | |
| 27 | void vmgenid_build_acpi(VmGenIdState *vms, GArray *table_data, GArray *guid, |
| 28 | BIOSLinker *linker, const char *oem_id) |
| 29 | { |
| 30 | Aml *ssdt, *dev, *scope, *method, *addr, *if_ctx; |
| 31 | uint32_t vgia_offset; |
| 32 | QemuUUID guid_le; |
| 33 | AcpiTable table = { .sig = "SSDT", .rev = 1, |
| 34 | .oem_id = oem_id, .oem_table_id = "VMGENID" }; |
| 35 | |
| 36 | /* Fill in the GUID values. These need to be converted to little-endian |
| 37 | * first, since that's what the guest expects |
| 38 | */ |
| 39 | g_array_set_size(guid, VMGENID_FW_CFG_SIZE - ARRAY_SIZE(guid_le.data)); |
| 40 | guid_le = qemu_uuid_bswap(vms->guid); |
| 41 | /* The GUID is written at a fixed offset into the fw_cfg file |
| 42 | * in order to implement the "OVMF SDT Header probe suppressor" |
| 43 | * see docs/specs/vmgenid.rst for more details |
| 44 | */ |
| 45 | g_array_insert_vals(guid, VMGENID_GUID_OFFSET, guid_le.data, |
| 46 | ARRAY_SIZE(guid_le.data)); |
| 47 | |
| 48 | /* Put VMGNEID into a separate SSDT table */ |
| 49 | acpi_table_begin(&table, table_data); |
| 50 | ssdt = init_aml_allocator(); |
| 51 | |
| 52 | /* Storage for the GUID address */ |
| 53 | vgia_offset = table_data->len + |
| 54 | build_append_named_dword(ssdt->buf, "VGIA"); |
| 55 | scope = aml_scope("\\_SB"); |
| 56 | dev = aml_device("VGEN"); |
| 57 | aml_append(dev, aml_name_decl("_HID", aml_string("QEMUVGID"))); |
| 58 | aml_append(dev, aml_name_decl("_CID", aml_string("VM_Gen_Counter"))); |
| 59 | aml_append(dev, aml_name_decl("_DDN", aml_string("VM_Gen_Counter"))); |
| 60 | |
| 61 | /* Simple status method to check that address is linked and non-zero */ |
| 62 | method = aml_method("_STA", 0, AML_NOTSERIALIZED); |
| 63 | addr = aml_local(0); |
| 64 | aml_append(method, aml_store(aml_int(0xf), addr)); |
| 65 | if_ctx = aml_if(aml_equal(aml_name("VGIA"), aml_int(0))); |
| 66 | aml_append(if_ctx, aml_store(aml_int(0), addr)); |
| 67 | aml_append(method, if_ctx); |
| 68 | aml_append(method, aml_return(addr)); |
| 69 | aml_append(dev, method); |
| 70 | |
| 71 | /* the ADDR method returns two 32-bit words representing the lower and |
| 72 | * upper halves * of the physical address of the fw_cfg blob |
| 73 | * (holding the GUID) |
| 74 | */ |
| 75 | method = aml_method("ADDR", 0, AML_NOTSERIALIZED); |
| 76 | |
| 77 | addr = aml_local(0); |
| 78 | aml_append(method, aml_store(aml_package(2), addr)); |
| 79 | |
| 80 | aml_append(method, aml_store(aml_add(aml_name("VGIA"), |
| 81 | aml_int(VMGENID_GUID_OFFSET), NULL), |
| 82 | aml_index(addr, aml_int(0)))); |
| 83 | aml_append(method, aml_store(aml_int(0), aml_index(addr, aml_int(1)))); |
| 84 | aml_append(method, aml_return(addr)); |
| 85 | |
| 86 | aml_append(dev, method); |
| 87 | aml_append(scope, dev); |
| 88 | aml_append(ssdt, scope); |
| 89 | |
| 90 | /* attach an ACPI notify */ |
| 91 | method = aml_method("\\_GPE._E05", 0, AML_NOTSERIALIZED); |
| 92 | aml_append(method, aml_notify(aml_name("\\_SB.VGEN"), aml_int(0x80))); |
| 93 | aml_append(ssdt, method); |
| 94 | |
| 95 | g_array_append_vals(table_data, ssdt->buf->data, ssdt->buf->len); |
| 96 | |
| 97 | /* Allocate guest memory for the Data fw_cfg blob */ |
| 98 | bios_linker_loader_alloc(linker, VMGENID_GUID_FW_CFG_FILE, guid, 4096, |
| 99 | false /* page boundary, high memory */); |
| 100 | |
| 101 | /* Patch address of GUID fw_cfg blob into the ADDR fw_cfg blob |
| 102 | * so QEMU can write the GUID there. The address is expected to be |
| 103 | * < 4GB, but write 64 bits anyway. |
| 104 | * The address that is patched in is offset in order to implement |
| 105 | * the "OVMF SDT Header probe suppressor" |
| 106 | * see docs/specs/vmgenid.rst for more details. |
| 107 | */ |
| 108 | bios_linker_loader_write_pointer(linker, |
| 109 | VMGENID_ADDR_FW_CFG_FILE, 0, sizeof(uint64_t), |
| 110 | VMGENID_GUID_FW_CFG_FILE, VMGENID_GUID_OFFSET); |
| 111 | |
| 112 | /* Patch address of GUID fw_cfg blob into the AML so OSPM can retrieve |
| 113 | * and read it. Note that while we provide storage for 64 bits, only |
| 114 | * the least-signficant 32 get patched into AML. |
| 115 | */ |
| 116 | bios_linker_loader_add_pointer(linker, |
| 117 | ACPI_BUILD_TABLE_FILE, vgia_offset, sizeof(uint32_t), |
| 118 | VMGENID_GUID_FW_CFG_FILE, 0); |
| 119 | |
| 120 | /* must be called after above command to ensure correct table checksum */ |
| 121 | acpi_table_end(linker, &table); |
| 122 | free_aml_allocator(); |
| 123 | } |
| 124 | |
| 125 | void vmgenid_add_fw_cfg(VmGenIdState *vms, FWCfgState *s, GArray *guid) |
| 126 | { |
| 127 | /* Create a read-only fw_cfg file for GUID */ |
| 128 | fw_cfg_add_file(s, VMGENID_GUID_FW_CFG_FILE, guid->data, |
| 129 | VMGENID_FW_CFG_SIZE); |
| 130 | /* Create a read-write fw_cfg file for Address */ |
| 131 | fw_cfg_add_file_callback(s, VMGENID_ADDR_FW_CFG_FILE, NULL, NULL, NULL, |
| 132 | vms->vmgenid_addr_le, |
| 133 | ARRAY_SIZE(vms->vmgenid_addr_le), false); |
| 134 | } |
| 135 | |
| 136 | static void vmgenid_update_guest(VmGenIdState *vms) |
| 137 | { |
| 138 | Object *obj = object_resolve_path_type("", TYPE_ACPI_DEVICE_IF, NULL); |
| 139 | uint32_t vmgenid_addr; |
| 140 | QemuUUID guid_le; |
| 141 | |
| 142 | if (obj) { |
| 143 | /* Write the GUID to guest memory */ |
| 144 | memcpy(&vmgenid_addr, vms->vmgenid_addr_le, sizeof(vmgenid_addr)); |
| 145 | vmgenid_addr = le32_to_cpu(vmgenid_addr); |
| 146 | /* A zero value in vmgenid_addr means that BIOS has not yet written |
| 147 | * the address |
| 148 | */ |
| 149 | if (vmgenid_addr) { |
| 150 | /* QemuUUID has the first three words as big-endian, and expect |
| 151 | * that any GUIDs passed in will always be BE. The guest, |
| 152 | * however, will expect the fields to be little-endian. |
| 153 | * Perform a byte swap immediately before writing. |
| 154 | */ |
| 155 | guid_le = qemu_uuid_bswap(vms->guid); |
| 156 | /* The GUID is written at a fixed offset into the fw_cfg file |
| 157 | * in order to implement the "OVMF SDT Header probe suppressor" |
| 158 | * see docs/specs/vmgenid.rst for more details. |
| 159 | */ |
| 160 | physical_memory_write(vmgenid_addr, guid_le.data, |
| 161 | sizeof(guid_le.data)); |
| 162 | /* Send _GPE.E05 event */ |
| 163 | acpi_send_event(DEVICE(obj), ACPI_VMGENID_CHANGE_STATUS); |
| 164 | } |
| 165 | } |
| 166 | } |
| 167 | |
| 168 | /* After restoring an image, we need to update the guest memory and notify |
| 169 | * it of a potential change to VM Generation ID |
| 170 | */ |
| 171 | static int vmgenid_post_load(void *opaque, int version_id) |
| 172 | { |
| 173 | VmGenIdState *vms = opaque; |
| 174 | vmgenid_update_guest(vms); |
| 175 | return 0; |
| 176 | } |
| 177 | |
| 178 | static const VMStateDescription vmstate_vmgenid = { |
| 179 | .name = "vmgenid", |
| 180 | .version_id = 1, |
| 181 | .minimum_version_id = 1, |
| 182 | .post_load = vmgenid_post_load, |
| 183 | .fields = (const VMStateField[]) { |
| 184 | VMSTATE_UINT8_ARRAY(vmgenid_addr_le, VmGenIdState, sizeof(uint64_t)), |
| 185 | VMSTATE_END_OF_LIST() |
| 186 | }, |
| 187 | }; |
| 188 | |
| 189 | static void vmgenid_handle_reset(void *opaque) |
| 190 | { |
| 191 | VmGenIdState *vms = VMGENID(opaque); |
| 192 | /* Clear the guest-allocated GUID address when the VM resets */ |
| 193 | memset(vms->vmgenid_addr_le, 0, ARRAY_SIZE(vms->vmgenid_addr_le)); |
| 194 | } |
| 195 | |
| 196 | static void vmgenid_realize(DeviceState *dev, Error **errp) |
| 197 | { |
| 198 | VmGenIdState *vms = VMGENID(dev); |
| 199 | |
| 200 | if (!bios_linker_loader_can_write_pointer()) { |
| 201 | error_setg(errp, "%s requires DMA write support in fw_cfg, " |
| 202 | "which this machine type does not provide", TYPE_VMGENID); |
| 203 | return; |
| 204 | } |
| 205 | |
| 206 | /* Given that this function is executing, there is at least one VMGENID |
| 207 | * device. Check if there are several. |
| 208 | */ |
| 209 | if (!find_vmgenid_dev()) { |
| 210 | error_setg(errp, "at most one %s device is permitted", TYPE_VMGENID); |
| 211 | return; |
| 212 | } |
| 213 | |
| 214 | qemu_register_reset(vmgenid_handle_reset, vms); |
| 215 | |
| 216 | vmgenid_update_guest(vms); |
| 217 | } |
| 218 | |
| 219 | static const Property vmgenid_device_properties[] = { |
| 220 | DEFINE_PROP_UUID(VMGENID_GUID, VmGenIdState, guid), |
| 221 | }; |
| 222 | |
| 223 | static void vmgenid_device_class_init(ObjectClass *klass, const void *data) |
| 224 | { |
| 225 | DeviceClass *dc = DEVICE_CLASS(klass); |
| 226 | |
| 227 | dc->vmsd = &vmstate_vmgenid; |
| 228 | dc->realize = vmgenid_realize; |
| 229 | device_class_set_props(dc, vmgenid_device_properties); |
| 230 | dc->hotpluggable = false; |
| 231 | set_bit(DEVICE_CATEGORY_MISC, dc->categories); |
| 232 | } |
| 233 | |
| 234 | static const TypeInfo vmgenid_device_info = { |
| 235 | .name = TYPE_VMGENID, |
| 236 | .parent = TYPE_DEVICE, |
| 237 | .instance_size = sizeof(VmGenIdState), |
| 238 | .class_init = vmgenid_device_class_init, |
| 239 | }; |
| 240 | |
| 241 | static void vmgenid_register_types(void) |
| 242 | { |
| 243 | type_register_static(&vmgenid_device_info); |
| 244 | } |
| 245 | |
| 246 | type_init(vmgenid_register_types) |